Special Application Fuses Intrinsically Safe > Surface Mount > 308 Series Pb RoHS 308 Series 30V Intrinsically Safe Fuse Description The 308 Series offers a range of surface mountable encapsulated fuses certified as intrinsically safe components that can be used in hazardous locations. Ideal for use in oil, gas, mine, chemical, pharmaceutical and process industries, the 308 Series surface mountable fuse was designed to limit the energy and temperature generated during its operation. The fuse design and its encapsulant are suitable for use in intrinsically safe apparatus and associated apparatus for peak voltage not exceeding 30V. Features Surface Mountable Suitable for use in Class I, Groups A, B, C and Encapsulated and sealed Agency Approvals D Class II, Groups E, (0.7mm minimum) F and G Class III and Designed for operation in Agency Agency File Number Ampere Rating Class I, Zone 0, AEx ia IIC a range of hazardous area DEMKO 15 ATEX 1439U Hazardous Locations. 0.250A 1.5A applications requiring (II 1 G Ex ia IIC) Suitable for use in Gas, 30V peak E358130 0.250A 1.5A Zone 0 Hazardous RoHS-compliant and lead- IECEx UL 15.0011U Locations per IEC and EN free 0.250A 1.5A (Ex ia IIC) 60079 Series Fully compatible with lead-free solder alloys Reference Standards and higher temperature profiles associated with Certification Standards lead-free assembly ATEX EN 60079-0, EN 60079-11 IECEx IEC 60079-0, IEC 60079-11 Applications UL 913, UL 60079-0, UL UL 60079-11 Testing, measuring or Process control and CAN/CSA C22.2 No. 157, processing electronic and automation cUL CAN/CSA C22.2 No. 60079-0, electrical equipment Sensors CAN/CSA C22.2 No. 60079-11 Motor controllers Lighting Communication handsets/ Flow/gas meters Electrical Characteristics for Series two-way radios % of Ampere Rating Opening Time 100% 4 Hours, Minimum 250%* 120 Seconds, Maximum 350%** 60 Seconds, Maximum * Applicable to 750mA - 1.5A ** Applicable to 250mA - 1.5A Electrical Specifications by Items Agency Approvals Ampere Nominal Minimum Cold Minimum Cold Nominal Cold Catalog Interrupting Rating Amp Code Melting Resistance at Resistance at Resistance at Number Rating 2 2 (A) I t (A Sec.) -20C (Ohms) -40C (Ohms) 25C (Ohms) 308.25 0.25 0.25 0.004 1.856 1.821 2.29 X X X 308.375 0.375 0.375 0.01 1.022 1.006 1.33 X X X 308.5 0.5 0.5 0.022 0.712 0.676 0.908 X X X 50A 24VAC 308.75 0.75 0.75 0.048 0.52 0.511 0.665 X X X 50A 30VDC 308001.0 1.0 1.0 0.1 0.226 0.216 0.42 X X X 3081.25 1.25 1.25 0.22 0.24 0.236 0.318 X X X 30801.5 1.5 1.5 0.333 0.182 0.144 0.209 X X X Notes: 1. The fuse must be mounted so that creepage and clearance distances arent impaired in any way. 2. The fuse is suitable for use in intrinsically safe equipment and associated apparatus for voltage not exceeding 30V peak. 3. Maximum surface temperature rise at 170% rated current: 250-375mA = 23C, 500mA = 35C, 750mA = 53C, 1A = 38C, 1.25-1.50A = 96C. 4. Minimum Cold Resistance at -30C is available upon request. 2020 Littelfuse, Inc. Specifications are subject to change without notice. Revised: GD. 10/14/20Special Application Fuses Intrinsically Safe > Surface Mount > 308 Series Temperature Rerating Curve Average Time Current Curves 140 100.000 120 100 80 10.000 60 40 -85-65 -45-25 -5 15 35 55 75 95 115135 155 1.000 TEMPERATURE (C) Notes: 1. Re-rating depicted in this curve is in addition to the standard re-rating of 20% for continuous operation. Example: For continuous operation at 55C, the fuse should be rerated as follows: I = (0.80)(0.90)I = (0.72)I RAT RAT 0.100 2. The temperature rerating curve represents the nominal conditions. For questions about temperature rerating curve, please consult Littelfuse technical support for assistance. 0.010 0.001 0.01 0.11 10 100 Current in Ampers Soldering Parameters Reflow Condition Pb Free assembly t P - Temperature Min (T ) 150C s(min) T P Critical Zone Pre Heat - Temperature Max (T ) 200C Ramp-up s(max) T to T L P - Time (Min to Max) (t ) 60 180 secs s T L t L Average ramp up rate (Liquidus Temp (T ) to peak 3C/second max. L T S(max) T to T - Ramp-up Rate 3C/second max. S(max) L Ramp-down - Temperature (T ) (Liquidus) 217C L Preheat Reflow T S(min) - Temperature (t ) 60 150 seconds L t S +0/5 Peak Temperature (T ) 260 C P Time within 5C of actual peak Temperature (t ) 30 Sec Max p 25 time to peak temperature Ramp-down Rate 6C/second max. Time (t 25C to peak) Time 25C to peak Temperature (T ) 8 minutes max. P Do not exceed - 2020 Littelfuse, Inc. Specifications are subject to change without notice. Revised: GD. 10/14/20 PERCENT OF RATING Time in Seconds 0.250A 0.375A 0.500A 0.750A 1.00A 1.25A 1.5A Temperature